Method of forming spliced sector cables



Dec. 23, 1952 M. D. BERGAN 2,622,314

METHOD OF FORMING SPLICED SECTOR CABLES Filed July 7, 1947 NW k r 3 I LK 1 7 "-1 E. l INVENTOR.

a /74/P77/V Q fiz/Pew/v mm dww.

Patented Dec. 23, 195 2 UNITED STATES PATENT OFFICE METHOD or FORMINGSPLICED SECTOR. GABLES Martin I). Bergan, Westfield; N. J.', assigno'rto The Thomas & Betts 00.; Elizabeth, N. J., a corporation of New JerseyA iiiicatimi juiy 7, 1947', serial No. 759,412

1 Claim.

The invention relates to the art br ath ng together the ends of electricconductors a; the type known as sector cables and also relates to theresulting article, w n V H w r In sector cables the conductors areformed of wire strands spirally twisted together lengthwise to form acore of such wires andwhich cores are somewhat elliptical in crosssection. More specifically defined conductors or sector cables andparticularly their stranded wire cores eachhave their radiiroun-ded intoeach other and into its arc side. The cores of sector cables are of twoforms, one compact and the other not compact. In the compact form theinitially round wire strands become polygonal shaped in cross section asa result of efforts to' get their core" cross s'ection of leastdimension and this is done during the manufacture of the cable. In thenoncom'pacted form, the wire strands are all in their initial shaperound in cross section with interstices formed between the wires Ingeneral, the invention relates broadly to the art of connecting sectorcables or conductors in end-to-end relation by means of a couplingsleeve into opposite ends of which the bared ends or the conductors areintruded, and the slee've is then squeezed and otherwise distorted intoa crimping engagement with both conductors. Usually such conductors areround in cross section and the coupling sleeves used therewith have abjore of cylindrical form and di'mensioned to receive the conductorstherein with a more or less snu fit. it has also been known in the artof sector shaped conductors to couple them together by means of acoupling sleeve the bore of which is of a sector shape and dimensionedto receive the sector cables fitted therein with a more or less snug fitand thus without intentional clearance provided therebetween before thesleeve is criinped there- The present invention contemplates animrovement in the technique of coupling together, by the use of acoupling sleeve, the ends f sectorshaped conductors of bo'th'th'ecompact and noncompact type and which coupler or splic'er' sleevesometimes referred to as a sector" cable s'plic'er is utilized tofunction not only as a connector but also as a former or tool forgivingshape to the portions of the conductors crimped' thereby.

The primary object of the invention insofar as its method aspects isconcerned is to cause: a relative shifting of the wire strands of thesector cables in passing from their initial circular or pressure toeffect a burnishin'g action suflicie'nt 2 to cause the wire strands tobreak through the oxide coatings usually formed on both the wires and onthe splicing sleeve, and thus to provide a low resistance joint betweenthe conductors and splicing sleeve incidental to the usual crimpingoperation. I

Briefly, this objective is attained by fitting the sector cable into theelliptical bore of a Sleeve relatively dimensioned sothat there will beinitially only the slight and necessary clearance between the cable andsleeve and then subjecting the sleeve to a distortion force under suchsqueeze pressure, as will in succession take u the clearance, will shiftthe strands of the portions of the conductor in the parts thereof socrimped which contract the cable and sleeve into; a smaller alloversection, and will eventually change the initial sector-elliptical formof the assembly into a compacted design of a different cross-sectionaldesign or non-circular geometric form, preferably into a small hex. V v

Briefly, this objective is attained by practicing the following steps;first, by rotating one after the other the sector cables to be joined,so as to match the ends of the bared conductors as they are brought intoalignment; second, by intruding the bared ends so rotatively matchedinto a splicing sleeve whose bore is elliptical or substantially so anddimensioned in both its major and minor axes to receive the associatedsector cable conductor, dimension for dimension, and with a sliding fit,and otherwise, relatedwith very little clearance between them; andfinally, to subject each end of the sleeve to at least one crimpingoperation to deform the sleeve and the portion of the conductor thereinto cause both of them to assume a highly compacted form hexagonal incross section.

The object of the invention relative to its mechanical aspect is toprovide a highly efilcie'nt mechanical and electrical connection betweencables the cores of at least one of which is of sector form.

Various other objects and advantages of the invention will be in partobvious from a consideration of the method features of the disclosureand from an inspection of the accompanying drawings and in part will bemore fully set forth in the following particular description of onemethod of practicing the invention, and the invention also consistsincertain new and novel modifications of the preferred method and otherfeatures of construction and combination of parts hereinafter set forthand claimed.

In the accompanying drawings:

Fig. 1 is a view in perspective of athree unit, non-compact sector cableof the type whose component sector conductors are intended to be splicedfollowing the invention herein disclosed and which also shows a pair ofconductor ends with a splicing sleeve in position thereon prior to beingcrimped on to the cores intruded therein;

Fig/2 is a transverse sectional view through any portion of either oneof the cables to be spliced;

Fig. 3 is a view of one conductor of each cable coupled in accordancewith the features herein disclosed; one half showing the coupling sleevein elevation and the other half in axial section;

Fig. 4 is a view partly in section taken on the line 4-4 of Fig. 1 andpartly in perspective showing the first step of the operation hereinfeatured with the elliptical sleeve loose on one of the sector conductorcores;

Figs. 5 to '7 inclusive are successive views in transverse section ofeither sector conductor taken at any one of the areas to be crimpedsuch, for instance, as on the line 'l'l of Fig. 3 and showing succeedingsteps of the sleeve and core being crimped by the coacting dies of acrimping too Fig. 5 showing the relation of sector core and ellipticalsleeve at the beginning of a crimping operation; Fig. 6 showing anintermediate stage featuring a fat elliptical form of the shifting core;and Fig. 7 showing the relation of hexagonal core and forming sleeve atthe completion of the crimping operation.

In the drawings and referring first to Figs. 1 and 2, for a showing ofone of the sector cables to be crimped, there is disclosed a cable A,which is formed of three sector conductors B, arranged in nestedrelation as shown in Fig. 2. These conductors B are of identical crosssec- .tional configuration so that the detailed description of one willbe sufficient for the other two. Each conductor includes a central coreC wrapped with an insulation D. The conductor cores C are formed oflongitudinally twisted wire strands E and which in the illustratedinstance are circular in cross section with interstices F therebetween.Cables of this character usually contain gas tubes G. the whole beingenclosed in a lead-sheet jacket H.

It is obvious that in connecting cables in endto-end relation, the leadsheet of each cab eis cut back to expose the ends of its conductors, andthe insulation of each cable is cut back to expose its wire strand core.The cables each considered as a Whole are relatively rotated so that theconductor ends of one cable will match those of the other in end-to-endalignment. The bared ends of conductor of each cable is then coupled tothe corresponding conductor of the other cable by a splicing sleeveparticularly constituting the novel feature of the apparatus aspect ofthis disclosure, so that in the case of the three conductor type ofcables herein illustrated, three coupling sleeves will be used. Thethree sleeves are finally disposed in parallel nested relation in thecompleted reformed and spliced cabled assembly.

Referring to Figs. 1 and i there is disclosed a connector splicing orcoupling sleeve H) which initially is of elliptical form with uniformcross section of material, it being particularly noted that its bore His substantially elliptical or perhaps more accurately described isdefined by a pair of parallel straight sides I2 and [3 rounding atopposite ends into'each other at top and bottom by means of edgesforming arched portions it and I5 and which edge portions are circularin cross section. The bore II is dimensioned to have an easy sliding butotherwise fairly snug fit on the wirestrand conductor C intrudedtherein. It is a feature of this disclosure that the clearance 5 betweenthe cable core C and the inner wall ll of the bore ll be of the leastpossible aggregate cross sectional area. In other words, the crosssectional area of the bore II is only so much greater than the crosssection of the core 0 as will permit the core to be intruded into thebore, taking into consideration that the sleeve is of the so-calledelliptical form herein featured and that the core is of the so-calledsector form in cross section.

Each pair of conductors are coupled together with one of these sleevesID by intruding the bared end of one of the conductors into one end ofthe sleeve and the bared ends of its companion sector cable conductor isintruded into its opposite end, the ends meeting at or adjacent to themedial plane a-b as indicated in Fig. 3. Opposite ends of the sleeve arethen subjected to the crimping action of a crimping tool as suggested inFigs. 5 to 7. In these figures the crimping tool is of the high pressureportable hydraulically operated type, the tool elements of which includea pair of coacting dies I and J, the opposing work faces of which aredefined by a three-sided recess K coacting when the dies are in theirfinal position to form the recess L hex in cross section as shown inFig. '7 and of less cross sectional area than the aggregate crosssectional area of the cable core and coupling sleeve when in theiroriginal uncrimped form as shown in Figs. 4 and 5.

Referring to Fig. 5 for the first step of the crimping operation, itwill be noted that the line of thrust lt of the dies I and J asindicated by the arrows is along the major axis of both the conductorcore C and splicing sleeve l0, and that initially the wire strands E arein whatever position they may happen to be in the balance of the cableas manufactured. As the dies are moved towards each other from theposition shown in Fig. 5, to and through the position shown in Fig. 6,the sleeve in the portion so being crimped, of course, tends to assumethe configuration of the recesses K in the die faces. During this timethe wire strands E tend to rearrange themselves one sliding on the otherand tending to assume at least momentarily the fat elliptical form shownin Fig. 6. This distension of the core has the effect of causing thestrands E as they slide past one another to break through any oxidecoating which maybe on the surfaces of the interior strands. At the sametime the outer strands are scraping against the bore wall I! of thecoupling sleeve likewise breaking through any oxide coating which may bepresent both on the bore wall and on the outer surfaces of the Wirestrands.

At the Fig. 6 stage the strands E are not so compact as they were at theinitial Fig. 5 stage. and the interstices F tend to become larger thanat other places along the length of the uncrimped core. However, thiscondition is only momentary but that is suflicient to break down anyintervening oxide layers on the strands. It is a feature of thisdisclosure to limit the possible play of the strands while held in. thesplicing sleeve.

As the dies approach their fully closed position as shown in Fig. 7, thewire strands become highly compacted even to the extent of losing theiroriginal form circular in cross section and assuming different polygonalforms with the practical elimination of any of their interstices so thatthe cross section of the cores at the points being crimped tend toapproach the aggregate cross sectional area of the strands themselves.

The sleeve at the points crimped likewise become compacted and assumethe hexagonal form of constricted and shortened perimeter shown in Fig.6. As the metal of the sleeve in the portion so crimped is thus worked,the crimped portion becomes slightly harder than the uncrimped portionsM between the crimped areas which retains their relative soft character.

In the illustrated form of the invention as disclosed in Fig. 3, fourcrimps, numbered from left to right as l, 2, 3 and 4, two at each coreend, are suggested, but it is obviously within the scope of thedisclosure to use one or more crimps for each conductor. I

The coupling sleeve is formed of soft copper particularly in those caseswhere the wire strands are of copper; however, it is obviously withinthe scope of the disclosure to utilize any materials usually employed incrimping tubes on to electric conductors.

Attention is particularly called to the fact that the sleeve does notsnugly fit the conductor core as is known in all prior similarconstructions. It

is necessary that some clearance I5 be provided initially between thecore and the sleeve, otherwise there would be no possibility of thegradual change in cross section configuration of the cores and theirwire strands as they pass from the more or less compacted form shown inFig. 5 through the relatively less un-compacted form shown in Fig. 7.Thus the disclosure facilitates the possibility of relative shifting ofthe wire strands one on the other to obtain a clean metalto-metalcontact which gives the effective splicing of the sector conductors toeach other as herein featured.

While the crimping into the hexagonal form is preferable it is withinthe scope of the disclosure otherwise to crimp the elliptical tube ontothe sector cable following any known crimpmethod. For instance theconnector tube may be crimped on to one or both of the sector conductorsby means of a die action which will produce six-sided elliptical hexagonor even a true elliptical form without any flat sides. In thisapplication the expression non-circular geometric form in cross sectionrefers generically to any non-circular symmetrical closed form outlinedby convex curves or angles connected by flat or convex curves and whosecross section may be a hexagon with flat sides and rounded convex anglesas shown in Fig. 7, or it may be an elliptical hexagon with curvedconvex sides, or it may be of a more or less true elliptical form withits endless convex curved outline.

I claim:

In the art of securing a stranded conductor whose cross sectioninitially is of sector form with rounded edges in a coupling sleeveinitially having an approximately elliptical cross section whose bore isdimensioned to receive the conductor dimension for dimension with asliding fi having parallel straight sides connected at opposite ends byrounded arched portions and wherein the cross sectional area of the boreof the sleeve is only slightly greater than the area in cross section ofthe conductor to minimize the aggregate area of clearances between theconductor and bore wall when the conductor is in the bore, by means of adie press of the type whose opposing work die faces are defined bythree-sided recesses coacting when the faces are closed in contact toform a recess hex in cross section, the method which consists inrelatively rotating the conductor and sleeve while free of each other tobring the major and minor axes of the conductor into alignment,respectively,

with the major and minor axes of the sleeve,

sliding the conductor axially when so rotated into the sleeve, placingthe sleeve with the conductor so located therein with the opposingrounded edges of the sleeve located in and substantially fitting in therecesses of the die work faces, causing the work faces of the die pressto approach each to effect a uni-directional squeeze action on thesleeve with its contained conductor in the direction of the common majoraxes of the sleeve and conductor and at a point in the squeeze actionprior to the closing of the work faces to reduce the initial dimensionsof both the sleeve and conductor as measured along their major axeswhile momentarily permitting both the sleeve and conductor to expand asmeasured along their minor axes thereby to cause the conductor to moveinto the form of a fat ellipse in cross section, more fully filling thebore than initially, with incidental rearrangement of the wire strandswhich make up the conductor, to cause them to slide one over the otherand to cause the conductor to open up and its interstices become largeras the conductor expands in the direction of its minor axis, continuingthe squeeze action of the die press to cause a sliding of the strands oneach other as the cross sectional area of the conductor contracts and.continuing the squeeze action until the die faces contact and thus todeform the sleeve bore and the portion of the conductor therein to causethe same to take a form hexagonal in cross section and to crimp the wallof the sleeve into a clean, direct, metal-to-metal engagement with theconductor with incidental final compressing of the conductor strands inthe portion so squeezed.

MARTIN D. BERGAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 650,860 Mc'Iighe June 5, 19001,727,895 Mraz Sept. 10, 1929 1,951,654 Green Mar. 20, 1934 2,050,855Oppenheim Aug. 11, 1936 2,188,178 Eby Jan. 23, 1940 2,247,928 TempleJuly 1, 1941 2,327,650 Klein Aug. 24, 1943 2,527,683 Warner et a1 Aug.24, 1943 2,427,518 Bergan Sept. 16, 1947

